Question

10. At what depth below the earth surface the value of g radius to one-half of its value on the earth's surface
A: R/4
B: R/2
C: R
4: 2R​

Answer 1

answer B (R/2)

The formula is g= GM/r^2

g/2=GM/r^2 ,g =GM/r^2/2 meaning distance from centre of mass is r/√2 which is 4525.48339959390 m from centre of mass of Earth .

g/4=GM/r^2 , g=GM/r^2/4 meaning distance from centre of mass is r/2 which is 3200m from the centre of mass of the earth.